I am studying for a test, and this is one of the practice questions:

A firm offers terms of 2/15, net 30. Currently, two-thirds of all
customers take advantage of the trade discount; the remainder pay
bills at the due date.
a. What will be the firm?s typical value for its accounts receivable period?
b. What is the average investment in accounts receivable if annual
sales are $20 million?
c. What would likely happen to the firm?s accounts receivable period
if it changed its terms
to 3/15, net 30?